EXOGENOUS OK DICOTYLEDONOUS PLANTS. 379 



* * * Calyx-tube adnate to the compound ovary. Stamens definite. 



Anthers opening by a pore at the apex. MBLASTOMACEiE. 

 Anthers opening longitudinally. 



Stipules between the petioles. Leaves opposite. Rhizophorace/e. 

 Stipules none. Calyx valvate. 



Cotyledons convolute. Fruit indehisoent, I'-eelled. Combketaoe^. 



Cotyledons plane. Fruit mostly 2- 4-celled. Onagkaoe^. 



Group 17. Ovary compound, one-celled, with parietal placentse. Petals and 

 (with one exception) stamens inserted on the throat of the calyx. Flowers 

 perfect, except in Papayacese. 



* Calyx adherent to the ovary. 



Albumen none or very little. Petals and stamens indefinite. Cactace^. 



Albumen very copious. Embryo minnte. Stamens 5. GeosstilacEjE. 



Albumen present. Embryo rather large. Stamens indefinite. LoASACE.a;. 



* * Calyx free from the ovary. 

 Flowers perfect. Stamens 5. 



Stamens distinct and perigynous. Tuenerace^. 



Stamens monadelphous, adnate to the gynophore. Passieloraoe^. 



Flowers dioecious. Stamens 10, on the corolla. Papayace.(E. 



Group 18. Ovary compound, one - several-celled, the placentae parietal (either 

 truly or falsely so). Calyx adnate. Corolla frequently monopetalous. 

 Stamens mostly united either by their filaments or anthers. Flowers 

 dioecious or monoecious. Albumen none. Succulent or tender vines with 

 tendrils. Cucuebitace.s:. 



Group 19. Ovaries two or more, many-ovuled, distinct, or partly, sometimes 

 completely, united, when the compound ovary is one-celled with parietal 

 placentaj, or 2 - many-celled with the placentae in the axis. Calyx eitlier 

 free from the ovary or more or less adherent to it. Petals and stamens 

 inserted on the calyx ; the latter mostly definite. Seeds albuminous, nu- 

 merous. 



Pistils of the same number as the sepals. Ceass0lace^. 



Pistils fewer than the sepals, more or less united. SAXiEKAGAOEiE. 



Group 20. Ovary compound, 2- (rarely 3 - 5-) celled, with a, single ovale sus- 

 pended from the apex of each cell. Stamens usually as many as the pet- 

 als or the lobes of the adherent calyx. Embryo small, in hard albumen. 



* Summit of the (often 2-lobed) ovary free from the calyx ; the petals and sta- 



mens inserted on the throat of the calyx. HamamelacejE. 



* * Calyx-tube entirely adherent to the ovary. Stamens and petals epigynous. 

 Fruit separable into two dry carpels. Flowers umbellate. Umbelufee^. 

 Fruit drupaceous, usually of more than two carpels. Akaliace^. 

 Fruit a 1 - 2-celled drupe. Flowers cymose or capitate. CoKNACEiE. 



